J. Fred Giertz (University of Illinois, Department of Economics) & Leslie E. Papke (Michigan State University, Department of Economics) have published Public Pension Plans: Myths and Realities for State Budgets, 60 Nat’l Tax J. 305 (2007).  Here is the abstract:

We explore the interaction of state pension systems with state finances. We find that changes in pension assets are an important source of funding for state governments, but that statesface incentive problems that impede funding efforts with the result that many plans are underfunded. We analyze the substantive differences between defined benefit and defined contribution plans for public employees and state governments. Regression analysis using a panel of 85 state public pension plans indicates some evidence of actuarial assumption manipulation to reduce funding pressure. Plan demographics and state tax revenues are significant influences on funding ratios, while plan features are not.